Does he really want to marry me?

My boyfriend and I have been together for 6 years. After 2 years, he said he would propose on our 3rd year anniversary (he has been open about marriage and we have talked a lot about it). Anyway, the anniversary came and went, with no ring. Then he promised Christmas... that came and went too. He later said his mum thinks men shouldn't get married until they are 30, and says although he doesn't intend to wait that long, he won't propose properly yet as it would upset his mum. Does he really want to marry me or is he putting his mum and her feelings before mine? He says he still wants to marry me and would get married tomorrow if he could! We have our own apartment, both got full time jobs and have talked about having kids as well. But his mum keeps saying she doesn't want to be a gran so we don't have them for a while! He is desperate for kids and I do get broody now and again as do most women, but if I mention babies around my boyfriend's mum he changes the subject 'because he doesn't want his mum to know we want kids'. (I'm a bit old fashioned and want to wait til I'm married before the kids come along). What should I do? I'm worried that he's still 'tied to the apron strings' and that it'll never change. His older brother split with his girlfriend as they were discussing baby names (not that they were planning for children at the time) and his mum overheard and disapproved! My dream is to get married and have kids with him, but at the same time I love him too much to let him go if I don't get that.